1. Field of the Invention
This invention relates to a semiconductor device and its manufacturing method, specifically to a packaged semiconductor device and its manufacturing method.
2. Description of the Related Art
A CSP (Chip Size Package) has received attention in recent years as a new packaging technology. The CSP means a small package having about the same outside dimensions as those of a semiconductor die packaged in it.
A BGA (Ball Grid Array) type semiconductor device has been known as a kind of CSP. The BGA type semiconductor device is provided with a plurality of ball-shaped conductive terminals that are electrically connected with pad electrodes disposed on a semiconductor substrate.
When the BGA type semiconductor device is mounted on electronic equipment, a semiconductor die housed in the BGA type semiconductor devise is electrically connected with an external circuit on a printed circuit board by bonding the conductive terminals to wiring patterns on the printed circuit board.
Such a BGA type semiconductor device is widely used because it has advantages in providing a large number of conductive terminals and in reducing size over other CSP type semiconductor devices such as an SOP (Small Outline Package) and a QFP (Quad Flat Package), which have lead pins protruding from their sides.
FIG. 22 is a cross-sectional view showing a structure of a conventional BGA type semiconductor device 110. A device component 101 such as a CCD (Charge Coupled Device) type image sensor or a CMOS type image sensor is formed in a top surface of a semiconductor substrate 100 made of silicon or the like. A pad electrode 102 is formed on the semiconductor substrate 100 through a first insulation film 103. A glass substrate 104, for example, is bonded to the top surface of the semiconductor substrate 100 through a resin layer 105 made of epoxy resin or the like. A second insulation film 106 made of a silicon oxide film or a silicon nitride film is formed on a side surface and a back surface of the semiconductor substrate 100.
A wiring layer 107 electrically connected with the pad electrode 102 is formed on the second insulation film 106. The wiring layer 107 is formed over the side surface and the back surface of the semiconductor substrate 100. A protection film 108 made of solder resist or the like is formed to cover the second insulation film 107 and the wiring layer 107. Openings are formed in the protection film 108 at predetermined regions on the wiring layer 107. There are formed ball-shaped conductive terminals 109 connected with the wiring layer 107 through the openings. The technology mentioned above is described in Japanese Unexamined Patent Publication No. 2002-512436.
In manufacturing the BGA type semiconductor devices, however, simplifying the manufacturing process and reducing the manufacturing cost have been required. In addition, reducing the thickness and the size of the BGA type semiconductor device has been required for higher packaging density. Also, there has been required a semiconductor device suitable for a small and high density stacked structure.